Renewable threaded liner for coal drill boxings



March 7, 1933. v. L. SCOTT ET AL RENEWABLE THREADED LINER FOR COAL DRILL BOXINGS\ Filed June 15, 1931 I N VEN TDRS:

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Patented Mar. 7, 1933 UNITED STATES VICTOR L. SCOTT, OF OT'IUMWA, IOWA, AND NICHOLAS W. MARSCH, F TROY, SOUTH DAKOTA Application filed .l'une 15, 1931. Serial No. 544,362.

, A vide an improved form of renewable thread ed liningsor bushings for the drill boxing, which is commonly made in sectional form to permit renewal of: the lining elements as these become worn, and the present invention provides not only a more easily replaced construction, but more durable design for the purpose.

Accordingly, the invention comprises a ree newable threaded lining or bushing structure adapted for convenient replacement, and also of a design adapted to prolong the life of the bushing by virtue of the increase in efficiency provided by the form of its construction and the mode of fitting it into the boxings, as well as the continuous uninterrupted form of thread which is provided for the operation of the drill bar.

With these and various other minor objects in view, the invention will now be described by reference to the accompanying 3'6 drawing illustrating one form of construction which we have devised for the embodiment of the various featuresof improvement, after which those features and combinations deem- 7 ed to be novel will be set forth and claimed] In the drawing Figure 1 is a plan View, illustrating a drill boxing equipped with a renewable lining or bushing construction embodying the pres- W ent features of improvement; and

taken on the lines 2 2 and 3-3, respectively, of Figure 1, portions of the bushing element being broken away in Figure 3.

Referring now to the drawing in detail, this illustrates the improved construction in its relation to a form of drill boxing com prising the two boxing sections 1, 5. formed with the arms 6 and 7, respectively, for hingedly connecting the boxing sections by means Figures 2 and 3 are transverse and longi tudinal sectional views, representing sections of a hinge bolt 8, as shown in Figures 1 and 2. On the opposite side of the boxing the section 4 is provided with extension lugs 9 adapted for latching engagement with the lateral extensions 10 formed on the clamping member 11 which is hingedly supported upon a bolt 12 mounted in arms 18 projecting from the corresponding side of the boxing section 5. The clamping member 11 is provided with a suitable operating handle 15, as usual.

In the present construction, the design of the boxing sections 4, 5, is such as to provide an interior boxing space of general hexagonal cross-section for engagement with the exterior faces of the lining or bushing sections 16 which, when matched together as illustrated in Figure 2, have a similar ex terior hexagonal contour, but so designed that the middle exterior face 17 of each of the sections 16 remains out of contact with what may be termed the interior bottom face of the corresponding boxing section when the remaining faces of the parts are in engagement.

This provides a boxing fit for the liner sections in which the main lateral faces of each section comprise continuous flat surfaces supported thefull length of the boxing upon the similar flat continuous faces of the corresponding boxing section while leaving a certain amount of clearance between the intermediate face 17 and the interior bottom face of the boxing section, for the purpose of accommodating wear to a certain extent during the life of the bushing. Likewise, on clamping the bushing sections in place by means of the clamping member 11, a certain amount of clearance is provided between the margins 18 of the boxing sections on the side next to the hinge 8 and also between the opposite edges 19, as clearly represented in Figure 2, the object of which is to insure firm clamping of the meeting edges of'the sections 16 together, without anycontacting of said edges 18 or 19 as the member 11 is swung into clamping position, the metal composing the clamping framework of the boxing permitting a sufiicient yielding of the parts to effect this latching operation. a

The boxing section 5 is formed with an extension lug 20 for which the other boxing section 4 is provided with a correspondingly shaped recess 21, accommodating said lug as represented in Figure 2, and likewise the liners or bushing sections 16 are formed upon their opposite meeting edges with similar mating recesses 22 also designed to receive the extension lug20, as illustrated. The lug 20 thus serves not only to lock the boxing sections in a manner tending to reinforce the action of the other connections between the boxing parts in opposing sidewise twisting or torsional movement, but by engagement with both sections 16 of the bushing locks the latter against any longitudinal shifting movement within the boxing, while also serving a supporting function at the points of engagement, at the recesses 22.

For retaining the boxing sections 16 within the boxing structure, as at times when the latter is opened for replacement purposes, or other attention, each section 16 is formed with a suitable lug 24 adapted to be projected through an opening 25 of the proper size in the bottom of each boxing section 4, 5, each lug 24 being formed with an opening or pas sage 26 adapted to receive the end of a .coil expansion spring 27, the coil portion 28 of which is mounted upon the middle portion of the bolt or pin 8. This manner of securing the bushing sections 16 in their operative position not only promotes the convenience of renewing the bushing sections 16 by the readiness with which the latter may be attached to the spring on being inserted into the boxing sections, but securely holds the bushings in place by the expansion action of the arms of the spring, and in effect prying them into seated relation within the boxing section as the spring arms operate around the adjacent exterior corners of the boxing, as

shown in Figure'2.

Various features of advantage characterize the improved construction, as above described. In the first place, the improved method of securing the liners or bushing sections within the boxing eliminates the use of bolts as commonly provided for the purpose, and hence the necessity of forming openings in the bushing sections for the passage of said bolts, and corresponding mutilation of the bushings and of the thread portions at those openings. Hence the present construction provides a continuous uninterrupted thread 14- throughout the length of the bushing structure. This results in a more efficient feed action by continuous engagement of the drill bar throughout the length of the boxing. Moreover a more nearly uniform thickness of stock in the bushing sections is possible by the improved design. with a more even wear as well as more uniform dissipation of any heat developed in the boring operation.

Again, the design and arrangement of the clamping surfaces between the bushing sections and the boxing sections provides a more eflicient mounting for the bushing structu e, in View of the greater extent of the clamping or supporting surfaces and the extension of the same throughout the length of the boxing; this eliminates the presence of unsupported areas to any appreciable extent, with a result that each convolution of the thread 14 is supported at a plurality of different radial points, and the spacing of the surfaces 17 at the outer faces of the bushing sections affords an ample range of adjustment of the bushing structure to take up wear during the life of the bushing elements. Again, it will be noted that the extension lug 20 serves a double function, that of holding the boxing sections locked against any material torsional or twisting tendencies, and also. by positive engagement with the recesses 22 of the liner sections, acts in cooperation with the projections 24 and boxing openings 25 to positively maintain the bushing structure against any longitudinal shifting movement. At the same time the ample bearing or cl amping surfaces between the bushing and boxing sections maintain the bushing parts against any possible rotative movement. the sections 16 being held firmly clamped together by the boxing sections without any meeting of the side margin of the latter due to the clearance provided at the edges 18 and 19. It will also be noted that the bushing sections are made standard and interchangeable. by providing the recesses 22 for the extension lug 20 at both of the side m argins of each section, and the sections otherwise fit the interior of the boxing members interchangeably.

A further feature of importance is the method employed for retaining the bushing elements within the boxing structure. by means of the sprin 27, the ends of whicn. hold the bushings in place upon opening of the boxing and thus prevent any displacement of the bushing sections until disengaged from the ends of the spring. and in the event of renewal of the bushing elements, the latter are readily disengaged upon removal of the bolt 8: and during this replacement operation there is not the liability of losing this spring as so often happens with the small coil spring commonly used merely for spreading open the boxing and having no other connection with the device. In the present construction therefore the spring employed serves the double function of spreading open the boxing structure. as well as maintaining the bushing elements in proper assembled relation within the boxing. The various parts are also of design requiring little machining, and such machining carried out, while the construction as a whole is easy and economical to manufacture.

It will therefore be apparent that we have devised a most practical and eflicient construction for fulfilling all the desired objects of our invention, and while we have shown and described what now appears to be the preferred form of embodiment of the improvements, we desire to reserve the right to make whatever changes or modifications may fairly fall within the scope of the appended claims.

Having described our invention, what we claim as new and desire to secure by Letters Patent is:

1. A drill boxing structure com-prising a pair of boxing sections, and threaded bushing sections enclosed within said boxing sections, said boxing and bushing sections having fiat engaging surfaces extending continuously the full length of the structure and of angular contourin cross-section with clearance provided between corresponding faces of said boxing and bushing sections for wear take-up.

2. A drill boxing structure comprising a pair of boxing sections, and threaded bushing sections enclosed within said boxing sections, the interior of said boxing andexterior of the assembled bushing sections being substantially hexagonal in cross-section providing flat engaging surfaces extending continuously the full length of the structure, with clearance provided between the middle faces of the bushing sections and corresponding'faces of the boxing sections for wear take-up.

3. A drill boxing structure comprising a pair of boxing sections, and threaded bushing sections enclosed within said boxing sections, and means carried by one boxing section for engagement with the other boxing section for preventing twisting tendencies of said sec-' tions and also effecting engagement with both bushing sections for positively preventing longitudinal shifting of the latter.

4. A drill boxing structure comprising a pair of boxing sections, and threaded bushing sections enclosed within said boxing sections, one of said boxing sections carrying a locking lug, the other boxing section being formed with a recess engaged by said lug to reinforce the boxing against twisting tendencies, said bushing sections being each formed with a recess also engaged by said lug for positively locking said bushing sections against longitudinal movement within the boxing.

5. A drill boxing structure comprising a pair of boxing sections, threaded bushing sections enclosed within said boxing sections,

' and a spring member operative to spread the boxing sections into open position and also efi'ective for holding said bushing sections in assembled relation within the boxing sections.

6. A drill boxing structure comprising a pair of boxing sections, threaded bushing sections enclosed within said boxing sections and cooperating to provide a continuous internal thread throughout the length of the boxing, and means operative to spread the boxing sections into open position and also acting to maintain said bushing sections in assembled relation within the boxing sections.

7. A drill boxing structure comprising a pair of boxing sections, threaded bushing sections enclosed within said boxing sections and cooperating to provide a continuous internal thread throughout the length of the boxing, and a single spring element operating to spread the boxing sections into open position and also engaged with said bushing sections for holding the latter in assembled relation within the boxing sections.

8. A drill boxing structure comprising a pair of boxing sections provided with a hinge connection, threaded bushing sections enclosed within said boxing sections, and a coil spring carried by said hinge connection and having terminal portions engaged with said bushing sections for maintaining the latter in assembled relation within the boxing sections.

9. A drill boxing structure comprising a pair of boxing sections. provided with a hinge connection, threaded bushing sections enclosed within said boxing sections and cooperating to provide a continuous internal thread throughout the length of the boxing, said bushing sections having lugs projecting out through the boxing sections, and a coil spring carried by said hinge connection and having terminal portions engaged with said lugs for maintaining the latter in assembled relation within said boxing sections.

10. A repair liner for sectional drill boxings comprising a pair of threaded bushing sections, and an expansion spring member provided with connections to the exterior of each of said bushing sections.

11. A repair liner for sectional drill boxings comprising a pair of threaded bushing sections cooperating to provide a continuous internal thread throughout their length, said bushing sections being formed with externally projecting lugs, and a coil spring having terminal portions engaged with said lugs for exerting a spreading action upon said bushing sections.

In witness whereof we hereunto afiix our signatures.

VICTOR L. SCOTT. NICHOLAS W. MARSGH. 

